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Your query returned 1 entry. 
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| EC | 6.5.1.5 | ||
| Accepted name: | RNA 3′-terminal-phosphate cyclase (GTP) | ||
| Reaction: | GTP + [RNA]-3′-(3′-phospho-ribonucleoside) = GMP + diphosphate + [RNA]-3′-(2′,3′-cyclophospho)-ribonucleoside (overall reaction) (1a) GTP + [RNA 3′-phosphate cyclase]-L-histidine = 5′-guanosyl [RNA 3′-phosphate cyclase]-Nτ-phosphono-L-histidine + diphosphate (1b) 5′-guanosyl [RNA 3′-phosphate cyclase]-Nτ-phosphono-L-histidine + [RNA]-3′-(3′-phospho-ribonucleoside) = [RNA 3′-phosphate cyclase]-L-histidine + [RNA]-3′-ribonucleoside-3′-(5′-diphosphoguanosine) (1c) [RNA]-3′-ribonucleoside-3′-(5′-diphosphoguanosine) = [RNA]-3′-(2′,3′-cyclophospho)-ribonucleoside + GMP |
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| Other name(s): | Pf-Rtc; RNA-3′-phosphate cyclase (GTP) | ||
| Systematic name: | RNA-3′-phosphate:RNA ligase (cyclizing, GMP-forming) | ||
| Comments: | The enzyme, which is specific for GTP, was characterized from the archaeon Pyrococcus furiosus. The enzyme converts the 3′-terminal phosphate of various RNA substrates into the 2′,3′-cyclic phosphodiester in a GTP-dependent reaction. Catalysis occurs by a three-step mechanism, starting with the activation of the enzyme by GTP, forming a phosphoramide bond between guanylate and a histidine residue. The guanylate group is then transferred to the 3′-phosphate terminus of the substrate, forming the capped structure [RNA]-3′-(5′-diphosphoguanosine). Finally, the enzyme catalyses an attack of the vicinal O-2′ on the 3′-phosphorus, which results in formation of cyclic phosphate and release of the guanylate. cf. EC 6.5.1.4, RNA-3′-phosphate cyclase (ATP). | ||
| Links to other databases: | BRENDA, EXPASY, KEGG, MetaCyc | ||
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